DE3112953C2 - Grinding wheel - Google Patents

Abstract

The invention relates to abrasive bodies with abrasive grain, for example corundum, an organic binder, for example phenolic resin, or an inorganic cold-binding binder, for example a phosphate binder, and an abrasive filler, at least some of the filler particles being made up of solids with a laminar layer structure, with a support grid, preferably made of graphite and a stored guest component.

Description

The invention relates to an abrasive body consisting of abrasive grain, an organic or cold-setting inorganic binder and optionally Coated abrasive graphite filler grains in connection with metal sulphides or halides (DE-OS 21 40 286).

The Use Of Fillers In Abrasive Grits Is known. The term fillers in the abrasive media industry includes practically the following 3 terms: i < >

1. Filler in the classic or usual sense for filling of plastics.

These have the following effects:

a) Resin savings *>

b) Reinforcement effects (reinforcement effect) and thus an increase in the strength of the binding web between the abrasive grains.

c) Reduction of the strength of the binding web and thus achieving a softer bond · »" and a milder cut. These fillers are inactive d. i.e. that during the grinding process no chemical and physical reactions that positively influence this process play. - ^

2. Fillers that support the manufacturing process, in particular the thermal curing of synthetic resins affect, e.g. B. magnesium oxide, calcium oxide.

3. "Abrasive fillers". These cause the .- " Grinding process chemical and physical processes that positively influence the grinding behavior.

The most important fillers In Schlelfschöhe masses are the grinding active fillers. Their effects can be divided ~ ^'5, In general, in the following three main groups:

1. Reduction of the friction between abrasive grain, workpiece and chips, ie the fillers or _w) their secondary products must act as high-temperature and high-pressure lubricants.

2. Protective effects through the formation of primary or secondary surface layers on the grain, workpiece and chips. "-

3. Cooling effects in the micro range.

For example, Halides (e.g. lead chloride, fluorspar, cryolite, etc.).

Chalcogenides (e.g. pyrite, ammonium sulphide, zinc sulphide, molybdenum sulphide, selenide, telluride etc.), low-melting Metals (e.g. lead, tin, mixed metals with a low melting point), high-pressure lubricants (e.g. graphite) proven.

In practice, however, numerous substances cannot be used or can only be used under special conditions. because they are expensive (precious metal halide, molybdenum sulfide), toxic (arsenic, selenium, lead compounds), are hygroscopic or easily soluble in water (numerous chlorides) or with the uncured phenolic resin system react strongly (hygroscopic chlorides) or reduce the pane strength (e.g. graphite, Sulfur).

Some of these materials, for example metal chlorides such as iron chloride (FeCl ₁ ), zinc chloride, tin chloride, potassium chloride and elemental sulfur are extremely abrasive and are also very inexpensive in terms of toxicity (high MAK value) and in terms of price.

The object of the invention is to create a grinding body in which the filler is extremely precise and also as high pressure and high temperature lubricants can be effective.

This is achieved according to the invention in that the metal sulfides or halides in the support lattice of the Graphite are embedded.

Preferred catfish referred to as storage compounds one substances in which in the lattice of an element or a compound other atoms, ions or molecules are embedded as "guest components", whereby the ratio of the atoms of the "host lattice" to those of the guest component is usually not stoichiometric. Examples are the metallic hydrides, carbides and nitricities of Ti, V, Mo, W and other transition metals. Such intercalation compounds with alkali metals were first found in graphite. Is characteristic of the polar graphite compounds the gradual storage: the reaction partner can enter any base-parallel layer gap of the graphite lattice (1st level), but it can also only fill every second, third, fourth, etc. gap (2nd, 3rd, 4th, etc. level). The regular storage is explained by the ionogenic Character of the connections, because the positively or negatively charged layers will endeavor to to be distributed over the grid with the same distance as possible. What these connections have in common is that they are more or less decomposed by water and at thermal decomposition or, in the case of reduction, turn back into graphite.

In addition to the compounds with a polar character, there are also Metallchlorld graphite intercalation compounds to be expected. They are only in large numbers in the last 10 years ago.

Vorzugswelse is provided that as a metal halide an Elsen-III-Chlorld connection is used.

One embodiment of the invention provides that an Elsen III chloride compound as the metal halide is used.

It has been shown that the combination of graphite with fillers that are at relatively low temperatures (up to approx. 400 °) split off water (e.g. calcium hydroxide), favorable grinding properties of the manufactured with it Abrasives, especially cool impact behavior, results.

The production of the grinding wheels takes place in the usual way Catfish. For example, the abrasive grain and the Filler particles wetted with a liquid phenolic resol.

Then the powdery bond, usually a mixture of a powdered novolak resin and fillers, added so that the grain and filler particles are coated. Then the Abrasives Pressed into molds and cured in ovens at around 18 (PC.

Of course, other manufacturing processes are also possible, as they are for hot-pressed, synthetic resin-bonded ones, for example Abrasives are common, applicable.

Execution example recipe:

Semi-precious corundum 24 mesh phenolic resol novolak resin

Filler particles of a graphite iron III chloride intercalation compound

% By weight 70% by weight 4 % by weight 8% by weight 10

Claims (3)

Patent claims: 1. Abrasive body, consisting of abrasive grain, an organic or cold-binding inorganic binder · ί medium and from abrasive graphite filler grains optionally provided with a coating with metal sulfides or metal halides, characterized in that the metal sulfides or halides in the support lattice of the graphite ι » are stored. 2. Abrasive body according to claim 1, characterized in that the metal halide is an iron-11 chloride compound is used. 3. Abrasive body according to claim 1, characterized in that i "> draws that the metal halide is an Elsen-IH chloride compound is used.